The present invention relates to implantable medical devices and systems, and more particularly to a implantable neural stimulation system and an external remote control unit used to control and monitor the implantable neural stimulation system. In a preferred embodiment, the implantable neural stimulation system comprises an auditory fully implantable system (FIS) adapted to provide selective electrical stimulation to the auditory nerve through electrodes implanted in the cochlea.
An auditory Fully Implantable System (FIS) is intended to be fully operational during normal use without the need for any external components. However, such FIS still requires an external control device in order to adjust various parameters of operation, such as stimulation intensity. Since there are no external controls provided with an FIS, there is a need for an external remote control device, or a remote control unit, to allow the various parameters of operation of the FIS to be controlled.
It is known in the art to use an acoustic remote control unit with a hearing aid system, including a hearing aid system that is at least partially implanted. See, e.g., international PCT publication WO97/01314, published on Jan. 16, 1997.
In U.S. Pat. No. 4,189,713, entitled “Remote Control Systems”, there is disclosed an acoustic remote control link wherein different value bits are transmitted as pulses containing different number of carrier cycles. Pulse-counting circuitry is then employed within the receiver to identify the received bits as either a “1” of a “0” on the basis of the received pulses containing numbers of carrier cycles in one or other of two ranges.
In U.S. Pat. No. 4,790,019, entitled “Remote Hearing Aid Volume Control”, a small hearing aid is disclosed, e.g., of the type worn behind the ear or even in the ear or the ear canal. Also disclosed is a remote sound wave control signal emitter that emits sound wave control signals within the range of the hearing aid microphone input. The control signals are used for the purpose of adjusting the volume/sensitivity of the hearing aid. Frequency selective circuitry is utilized inside the hearing aid to separate control signal components from normal to-be-heard signal components. A frequency shift keying (FSK) type of modulation is suggested as one type of modulation for the control signal. In one embodiment, the control signal emitter emits a carrier frequency outside of the receiving range of the hearing aid earphone, preferably above the receiving range of the earphone, thereby rendering the control signals inaudible to the hearing aid user.
In U.S. Pat. No. 4,845,755, entitled “Remote Control Hearing Aid”, there is taught a hearing aid with a wireless remote control in which the microphone of the hearing aid is used as the receiving element for the control signals. The wideband nature of the miniature microphone is relied upon to sense incoming control signals that are imperceptible to the human ear, e.g., signals in the ultrasonic range up to 25 KHz, or signals that utilize resonance properties of the microphone between 45 KHz and 59 KHz.
In U.S. Pat. No. 4,918,736, entitled “Remote Control System For Hearing Aids”, the combination of a hearing aid adapted to be supported upon the head of a user and a remote control unit is shown. The remote control unit provides control of an operational parameter of the hearing aid, such as the amplification factor, so that the hearing aid can remain rather small and occupy a smaller amount of space. The wireless transmission fo the control signal from the remote control unit is by means of acoustic waves. The microphone of the hearing aid functions as the pick-up for receiving the control signal from the remote control unit. The control signal lies in a frequency region which is outside of the operating range of the electro-acoustic transducer of the hearing aid, but still within the frequency range of the microphone. The control signal is used to switch the hearing aid on or off, change volume, frequency settings or other operational parameters, without disturbing the user of the hearing aid. The acoustic control signal may be modulated, e.g., with AM, FM, or DTMF modulation.
Additionally, in U.S. Pat. No. 5,083,312, entitled “Programmable Multichannel Hearing Aid with Adaptive Filter”, there is taught a small hearing aid device, preferably an in-the-canal hearing aid, that may be conveniently and inexpensively programmed with remotely generated audible signals. The preferred audio programming signal disclosed in the '312 patents consists of dual-tone multiple-frequency (DTMF) tones. One of the stated advantages of using DTMF tones is that clinicians can reprogram the hearing aid on site or over the telephone. Further, by using a unique command sequence as the programming signal, the possibility of inadvertent programming due to ordinary speaking or other environmental sound patterns, is greatly minimized.
Thus, it is seen, that remotely-generated acoustic signals have long been used to program or control a hearing aid device or system. However, none of the teachings of the prior art specifically address how to program or control a fully implantable system (FIS).